linux/include/linux/spinlock.h
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   1#ifndef __LINUX_SPINLOCK_H
   2#define __LINUX_SPINLOCK_H
   3
   4/*
   5 * include/linux/spinlock.h - generic spinlock/rwlock declarations
   6 *
   7 * here's the role of the various spinlock/rwlock related include files:
   8 *
   9 * on SMP builds:
  10 *
  11 *  asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the
  12 *                        initializers
  13 *
  14 *  linux/spinlock_types.h:
  15 *                        defines the generic type and initializers
  16 *
  17 *  asm/spinlock.h:       contains the arch_spin_*()/etc. lowlevel
  18 *                        implementations, mostly inline assembly code
  19 *
  20 *   (also included on UP-debug builds:)
  21 *
  22 *  linux/spinlock_api_smp.h:
  23 *                        contains the prototypes for the _spin_*() APIs.
  24 *
  25 *  linux/spinlock.h:     builds the final spin_*() APIs.
  26 *
  27 * on UP builds:
  28 *
  29 *  linux/spinlock_type_up.h:
  30 *                        contains the generic, simplified UP spinlock type.
  31 *                        (which is an empty structure on non-debug builds)
  32 *
  33 *  linux/spinlock_types.h:
  34 *                        defines the generic type and initializers
  35 *
  36 *  linux/spinlock_up.h:
  37 *                        contains the arch_spin_*()/etc. version of UP
  38 *                        builds. (which are NOPs on non-debug, non-preempt
  39 *                        builds)
  40 *
  41 *   (included on UP-non-debug builds:)
  42 *
  43 *  linux/spinlock_api_up.h:
  44 *                        builds the _spin_*() APIs.
  45 *
  46 *  linux/spinlock.h:     builds the final spin_*() APIs.
  47 */
  48
  49#include <linux/typecheck.h>
  50#include <linux/preempt.h>
  51#include <linux/linkage.h>
  52#include <linux/compiler.h>
  53#include <linux/irqflags.h>
  54#include <linux/thread_info.h>
  55#include <linux/kernel.h>
  56#include <linux/stringify.h>
  57#include <linux/bottom_half.h>
  58#include <asm/barrier.h>
  59
  60
  61/*
  62 * Must define these before including other files, inline functions need them
  63 */
  64#define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
  65
  66#define LOCK_SECTION_START(extra)               \
  67        ".subsection 1\n\t"                     \
  68        extra                                   \
  69        ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  70        LOCK_SECTION_NAME ":\n\t"               \
  71        ".endif\n"
  72
  73#define LOCK_SECTION_END                        \
  74        ".previous\n\t"
  75
  76#define __lockfunc __attribute__((section(".spinlock.text")))
  77
  78/*
  79 * Pull the arch_spinlock_t and arch_rwlock_t definitions:
  80 */
  81#include <linux/spinlock_types.h>
  82
  83/*
  84 * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
  85 */
  86#ifdef CONFIG_SMP
  87# include <asm/spinlock.h>
  88#else
  89# include <linux/spinlock_up.h>
  90#endif
  91
  92#ifdef CONFIG_DEBUG_SPINLOCK
  93  extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
  94                                   struct lock_class_key *key);
  95# define raw_spin_lock_init(lock)                               \
  96do {                                                            \
  97        static struct lock_class_key __key;                     \
  98                                                                \
  99        __raw_spin_lock_init((lock), #lock, &__key);            \
 100} while (0)
 101
 102#else
 103# define raw_spin_lock_init(lock)                               \
 104        do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
 105#endif
 106
 107#define raw_spin_is_locked(lock)        arch_spin_is_locked(&(lock)->raw_lock)
 108
 109#ifdef CONFIG_GENERIC_LOCKBREAK
 110#define raw_spin_is_contended(lock) ((lock)->break_lock)
 111#else
 112
 113#ifdef arch_spin_is_contended
 114#define raw_spin_is_contended(lock)     arch_spin_is_contended(&(lock)->raw_lock)
 115#else
 116#define raw_spin_is_contended(lock)     (((void)(lock), 0))
 117#endif /*arch_spin_is_contended*/
 118#endif
 119
 120/* The lock does not imply full memory barrier. */
 121#ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
 122static inline void smp_mb__after_lock(void) { smp_mb(); }
 123#endif
 124
 125/**
 126 * raw_spin_unlock_wait - wait until the spinlock gets unlocked
 127 * @lock: the spinlock in question.
 128 */
 129#define raw_spin_unlock_wait(lock)      arch_spin_unlock_wait(&(lock)->raw_lock)
 130
 131#ifdef CONFIG_DEBUG_SPINLOCK
 132 extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
 133#define do_raw_spin_lock_flags(lock, flags) do_raw_spin_lock(lock)
 134 extern int do_raw_spin_trylock(raw_spinlock_t *lock);
 135 extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
 136#else
 137static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
 138{
 139        __acquire(lock);
 140        arch_spin_lock(&lock->raw_lock);
 141}
 142
 143static inline void
 144do_raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long *flags) __acquires(lock)
 145{
 146        __acquire(lock);
 147        arch_spin_lock_flags(&lock->raw_lock, *flags);
 148}
 149
 150static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 151{
 152        return arch_spin_trylock(&(lock)->raw_lock);
 153}
 154
 155static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 156{
 157        arch_spin_unlock(&lock->raw_lock);
 158        __release(lock);
 159}
 160#endif
 161
 162/*
 163 * Define the various spin_lock methods.  Note we define these
 164 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The
 165 * various methods are defined as nops in the case they are not
 166 * required.
 167 */
 168#define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
 169
 170#define raw_spin_lock(lock)     _raw_spin_lock(lock)
 171
 172#ifdef CONFIG_DEBUG_LOCK_ALLOC
 173# define raw_spin_lock_nested(lock, subclass) \
 174        _raw_spin_lock_nested(lock, subclass)
 175
 176# define raw_spin_lock_nest_lock(lock, nest_lock)                       \
 177         do {                                                           \
 178                 typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
 179                 _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
 180         } while (0)
 181#else
 182# define raw_spin_lock_nested(lock, subclass)           _raw_spin_lock(lock)
 183# define raw_spin_lock_nest_lock(lock, nest_lock)       _raw_spin_lock(lock)
 184#endif
 185
 186#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 187
 188#define raw_spin_lock_irqsave(lock, flags)                      \
 189        do {                                            \
 190                typecheck(unsigned long, flags);        \
 191                flags = _raw_spin_lock_irqsave(lock);   \
 192        } while (0)
 193
 194#ifdef CONFIG_DEBUG_LOCK_ALLOC
 195#define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 196        do {                                                            \
 197                typecheck(unsigned long, flags);                        \
 198                flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
 199        } while (0)
 200#else
 201#define raw_spin_lock_irqsave_nested(lock, flags, subclass)             \
 202        do {                                                            \
 203                typecheck(unsigned long, flags);                        \
 204                flags = _raw_spin_lock_irqsave(lock);                   \
 205        } while (0)
 206#endif
 207
 208#else
 209
 210#define raw_spin_lock_irqsave(lock, flags)              \
 211        do {                                            \
 212                typecheck(unsigned long, flags);        \
 213                _raw_spin_lock_irqsave(lock, flags);    \
 214        } while (0)
 215
 216#define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
 217        raw_spin_lock_irqsave(lock, flags)
 218
 219#endif
 220
 221#define raw_spin_lock_irq(lock)         _raw_spin_lock_irq(lock)
 222#define raw_spin_lock_bh(lock)          _raw_spin_lock_bh(lock)
 223#define raw_spin_unlock(lock)           _raw_spin_unlock(lock)
 224#define raw_spin_unlock_irq(lock)       _raw_spin_unlock_irq(lock)
 225
 226#define raw_spin_unlock_irqrestore(lock, flags)         \
 227        do {                                                    \
 228                typecheck(unsigned long, flags);                \
 229                _raw_spin_unlock_irqrestore(lock, flags);       \
 230        } while (0)
 231#define raw_spin_unlock_bh(lock)        _raw_spin_unlock_bh(lock)
 232
 233#define raw_spin_trylock_bh(lock) \
 234        __cond_lock(lock, _raw_spin_trylock_bh(lock))
 235
 236#define raw_spin_trylock_irq(lock) \
 237({ \
 238        local_irq_disable(); \
 239        raw_spin_trylock(lock) ? \
 240        1 : ({ local_irq_enable(); 0;  }); \
 241})
 242
 243#define raw_spin_trylock_irqsave(lock, flags) \
 244({ \
 245        local_irq_save(flags); \
 246        raw_spin_trylock(lock) ? \
 247        1 : ({ local_irq_restore(flags); 0; }); \
 248})
 249
 250/**
 251 * raw_spin_can_lock - would raw_spin_trylock() succeed?
 252 * @lock: the spinlock in question.
 253 */
 254#define raw_spin_can_lock(lock) (!raw_spin_is_locked(lock))
 255
 256/* Include rwlock functions */
 257#include <linux/rwlock.h>
 258
 259/*
 260 * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
 261 */
 262#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 263# include <linux/spinlock_api_smp.h>
 264#else
 265# include <linux/spinlock_api_up.h>
 266#endif
 267
 268/*
 269 * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
 270 */
 271
 272static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 273{
 274        return &lock->rlock;
 275}
 276
 277#define spin_lock_init(_lock)                           \
 278do {                                                    \
 279        spinlock_check(_lock);                          \
 280        raw_spin_lock_init(&(_lock)->rlock);            \
 281} while (0)
 282
 283static inline void spin_lock(spinlock_t *lock)
 284{
 285        raw_spin_lock(&lock->rlock);
 286}
 287
 288static inline void spin_lock_bh(spinlock_t *lock)
 289{
 290        raw_spin_lock_bh(&lock->rlock);
 291}
 292
 293static inline int spin_trylock(spinlock_t *lock)
 294{
 295        return raw_spin_trylock(&lock->rlock);
 296}
 297
 298#define spin_lock_nested(lock, subclass)                        \
 299do {                                                            \
 300        raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 301} while (0)
 302
 303#define spin_lock_nest_lock(lock, nest_lock)                            \
 304do {                                                                    \
 305        raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);       \
 306} while (0)
 307
 308static inline void spin_lock_irq(spinlock_t *lock)
 309{
 310        raw_spin_lock_irq(&lock->rlock);
 311}
 312
 313#define spin_lock_irqsave(lock, flags)                          \
 314do {                                                            \
 315        raw_spin_lock_irqsave(spinlock_check(lock), flags);     \
 316} while (0)
 317
 318#define spin_lock_irqsave_nested(lock, flags, subclass)                 \
 319do {                                                                    \
 320        raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 321} while (0)
 322
 323static inline void spin_unlock(spinlock_t *lock)
 324{
 325        raw_spin_unlock(&lock->rlock);
 326}
 327
 328static inline void spin_unlock_bh(spinlock_t *lock)
 329{
 330        raw_spin_unlock_bh(&lock->rlock);
 331}
 332
 333static inline void spin_unlock_irq(spinlock_t *lock)
 334{
 335        raw_spin_unlock_irq(&lock->rlock);
 336}
 337
 338static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 339{
 340        raw_spin_unlock_irqrestore(&lock->rlock, flags);
 341}
 342
 343static inline int spin_trylock_bh(spinlock_t *lock)
 344{
 345        return raw_spin_trylock_bh(&lock->rlock);
 346}
 347
 348static inline int spin_trylock_irq(spinlock_t *lock)
 349{
 350        return raw_spin_trylock_irq(&lock->rlock);
 351}
 352
 353#define spin_trylock_irqsave(lock, flags)                       \
 354({                                                              \
 355        raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 356})
 357
 358static inline void spin_unlock_wait(spinlock_t *lock)
 359{
 360        raw_spin_unlock_wait(&lock->rlock);
 361}
 362
 363static inline int spin_is_locked(spinlock_t *lock)
 364{
 365        return raw_spin_is_locked(&lock->rlock);
 366}
 367
 368static inline int spin_is_contended(spinlock_t *lock)
 369{
 370        return raw_spin_is_contended(&lock->rlock);
 371}
 372
 373static inline int spin_can_lock(spinlock_t *lock)
 374{
 375        return raw_spin_can_lock(&lock->rlock);
 376}
 377
 378#define assert_spin_locked(lock)        assert_raw_spin_locked(&(lock)->rlock)
 379
 380/*
 381 * Pull the atomic_t declaration:
 382 * (asm-mips/atomic.h needs above definitions)
 383 */
 384#include <linux/atomic.h>
 385/**
 386 * atomic_dec_and_lock - lock on reaching reference count zero
 387 * @atomic: the atomic counter
 388 * @lock: the spinlock in question
 389 *
 390 * Decrements @atomic by 1.  If the result is 0, returns true and locks
 391 * @lock.  Returns false for all other cases.
 392 */
 393extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 394#define atomic_dec_and_lock(atomic, lock) \
 395                __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 396
 397#endif /* __LINUX_SPINLOCK_H */
 398
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